Android Tutorial Walkie Talkie - Audio streaming over Wifi or Bluetooth

This example implements a simple "walkie talkie".

(src: wikipedia)

Once the two devices are connected, either over Bluetooth or over the local network, you can press on the activity and talk. The audio captured from the microphone will be sent to the other device and played. Note that this is a half duplex solution, which means that audio will not be received while you send audio. This is to avoid positive feedback (which will also occur if the devices are close to each other).

Most of the code handles the connection. Streaming the audio is done with AudioStreamer object which was introduced in Audio library v1.5.

Note that if you are only interested in audio recording then you should follow the two examples in the above link.

The "interesting" code that is responsible for capturing the audio and sending it is quite simple:

Sub AudioStream_RecordBuffer (Data() As Byte)
   If sendingAudio Then
      astream.Write(Data)
   End If
End Sub

Then in the other side:

Sub astream_NewData (Buffer() As Byte)
   If sendingAudio = False Then
      'play the received audio data
      audioStream.Write(Buffer)
   End If
End Sub

 

[kris_audi]

I use Samsung GT-S5830i with Android version 2.3.6.

 

[Erel]

I think that I see the cause of this problem. Try a different set of parameters. Your device doesn't support the current values.

 

[kris_audi]

I use SampleRate 44100 instead of 22050 this error goes away.
Thank you Erel.

 

[mauro56]

Hi,
after updating my Nexus 7 to Android 4.4.2 now I have an error and the application Walkie Talkie crashes unexpectedly. The problem seems to be in the service module "Connector". More precisely, in the subroutine:

Public Sub StopSendingAudio
audioStream.StopRecording
sendingAudio = False
end Sub

It seems to be the audiostream.StopRecording that causes abnormal termination.
With the previous version (Android 4.4.3) Walkie Talkie application works correctly.

 

[Erel]

Can you post the error from the logs?

Does it also crash with the example here: http://www.b4x.com/android/forum/threads/audio-library-v1-5-new-audiostreamer-object.30550/ ?

 

[mauro56]

Yes, I have the same problem with the example you indicated, although less frequently. I am enclosing a few lines of the log when the error hoping you find it useful.
I correct a mistake in my previous post. The previous version of Android is 4.3.0. With this version everything is ok.

** Service (service1) Destroy **
** Service (service1) Create **
** Service (service1) Start **
Connected to B4A-Bridge (Wifi)
Installing file.
** Activity (main) Pause, UserClosed = false **
PackageAdded: package:b4a.audiostreamerex
** Activity (main) Create, isFirst = true **
** Activity (main) Resume **
java.lang.NegativeArraySizeException: -3
at anywheresoftware.b4a.audio.AudioStreamer$Recorder.run(AudioStreamer.java:145)
at java.lang.Thread.run(Thread.java:841)
** Activity (main) Pause, UserClosed = true **
** Activity (main) Resume **
** Activity (main) Pause, UserClosed = false **
Installing file.
PackageAdded: package:b4a.audiostreamerex
** Activity (main) Create, isFirst = true **
** Activity (main) Resume **
java.lang.NegativeArraySizeException: -3
at anywheresoftware.b4a.audio.AudioStreamer$Recorder.run(AudioStreamer.java:145)
at java.lang.Thread.run(Thread.java:841)
** Activity (main) Pause, UserClosed = true **

Thank you for your attention.

 

[Erel]

I tested the second example with Android 4.4.2 (Nexus 4) and it ran properly. You said that it happened less frequently. When did it happen? When you started recording?

 

[mauro56]

Yes, when you start the recording. And 'less frequent if you remain silent. If you register for a few seconds and close the recording application crashes. In the example of Walkie Talkies is definitely more common, but even in this final example at least once in two the application crashes. Always close when recording.

 

[Erel]

I've uploaded an updated version: Audio library v1.5 - New AudioStreamer object

It should fix this issue.

 

[mauro56]

Thank you Erel. Now is OK on both examples.

 

[wm.chatman]

Can't compile the Walkie Talkie Sample.

Compiling code. Error
Error parsing program.
Error description: Unknown type: audiostreamer
Are you missing a library reference?
Occurred on line: 18
Private audioStream As AudioStreamer

Audio 1.3 is avail.

what's up, any thoughts on this one ?

 

[klaus]

You need the Audio library version 1.5 as indicated in the first post.

 

[wm.chatman]

I did 4 x. Does not seem to work.

 

[Erel]

Do you get the same error?

 

[wm.chatman]

yes I do Erel.

 

[Erel]

Make sure that you copied the updated Audio library to the internal libraries folder. You can see the version in the libraries tab. If it isn't 1.5 then you didn't copy it to the correct place.

 

[wm.chatman]

Erel,

I did from here. I deleted the old Audio files and pastes the new downloaded.
In the design area I checkt Audio again. Still shows 1.30 v

http://www.b4x.com/android/forum/threads/audio-library-v1-5-new-audiostreamer-object.30550/

 

[Erel]

Make sure that you deleted the Audio library (both files) from both libraries folders. The internal one (under program files) and the additional one.

 

[ericvanderhoeven]

This example implements a simple "walkie talkie".

This app works fine here on 2 tablets both fitted with Wifi AND Bluetooth. It does not seem to work on 2 tablets with wifi only.
Could that be the reason (that it does not have bluetooth)?
And if so, what lines to take out of the sample code?
On the wifi only tablets, it spits out quite a nasty (and lengthy) error log when I try to run it. On the combo tablets, no error log at all.

Any help is appreciated.

Thx,

Eric

 

[Erel]

Can you post the error message?

Go over the code, it should be simple to remove all the Bluetooth related code.